DISSERTATION PERFORMANCE ASSESSMENT OF SIMPLE BLAST WALL SYSTEMS Submitted by Assal Hussein Department of Civil and Environmental Engineering In partial fulfillment of the requirements For the Degree of Doctor of Philosophy Colorado State University Fort Collins, Colorado Spring 2019 Doctoral Committee: Advisor: Hussam N. Mahmoud Co-Advisor: Paul R. Heyliger John W. van de Lindt David I. McLean Jennifer L. Mueller Copyright by Assal Hussein 2019 All Rights Reserved ABSTRACT PERFORMANCE ASSESSMENT OF SIMPLE BLAST WALL SYSTEMS Numerous planned suicide attacks have been recorded since the beginning of the current century in several regions of the world. These attacks have impacted huge number of victims and have resulted in economic and psychological consequences on communities and nations, with complex global influences at times. In recent years, terrorist organizations have adopted new strategies that have made it difficult for security and intelligence operations to stop attacks. The main objectives of this dissertation are 1) draw the attention to the benefit of considering simple blast wall systems to mitigate the hazard of the suicide attacks, 2) determining the efficiency of readily available materials in dissipating the blast of shock wave energy, and 3) to investigate the performance of simple blast wall systems. This study discusses the threat of suicide attacks that are executed by bombers wearing vests and provides a general view of this type of man- made hazard and its consequences on the existence of communities and their future. The study clarified the impacts of suicide attacks in the Republic of Iraq, and the U.S. Muqdadiyah City was considered as a case study of these impacts in the Republic of Iraq. The results of the literature review highlighted the necessity to adopt a new approach to designing simple blast wall systems. Designing such systems made of low-tech materials can mitigate and reduce losses from such type of threat, make their implementation easier and more cost-effective, and potentially result in a reduction in death, injury, and damage. ii Different engineering methods have been investigated and considered for civilian and military fields to mitigate blast shock wave effects. Standards and technical manuals have been published by federal agencies and research centers to set general safety precautions and/or structural design approaches, charts, and equations. However, many of these manuals are limited and not released to the public. In addition to a lack of funds, the technology of construction, and availability of high-tech materials, designing blast- resistant structures or high-tech blast wall systems are not an available option for designers in most developing countries. Design guidelines are sparse if not non-existent. This research was focused on suggesting a new blast wall system using low-tech materials to mitigate the effect of a blast shock wave in free-air. The oriented stands board (OSB) and wood-sand-wood (WSaW) blast walls were considered in the current study as examples of blast walls made of readily available materials that can be installed with minimal effort. The response of these structural systems was investigated experimentally, and results verified with numerical analysis results. Moreover, distribution of free-air blast pressure was measured and compared with the Kingery-Bulmash reference measurements for a wide variety of explosive charges. A good agreement was noticed between the measured blast pressure and Kingery-Bulmash model. The numerical analysis was implemented using 3-D-dynamic finite element method (3-D-FEM). The commercial software ABAQUS/Explicit version 6.14 combined with ConWep blast loading model as inbuilt blast load function was considered to represent the interactions between blast wave and the wall. The numerical analysis results of a WSaW blast wall showed a good agreement with test results. iii In addition to the focus on wall systems, initial efforts were made to measure damage to humans. Eardrum rupture is one of the main injuries due to blast shock wave and could lead to temporary and permanent hearing loss. In this study, the blast shock wave intensity on eardrum has been investigated experimentally. Due to the similarity between the sheep ear structure and human ear, five Rambouillet-Columbia sheep heads samples were subjected to blast shock wave. The measured blast pressure exceeded the threshold of eardrum rupture. This means that the threshold for eardrum rupture was already surpassed and a 50 percent probability of eardrum rupture is expected. The micro-CT images showed the structure of the eardrum is totally ruptured. Three eardrum samples on the right side were ruptured, while only two samples on the left side were ruptured. The probability of temporary hearing loss injury could take place at level of pressure less than the threshold which can be considered the starting point of eardrum rupture (UFC 3-340-02). These experiments are described in this dissertation. Finally, a probabilistic analysis of an equivalent single-degree of freedom (SDOF) system was completed for WSaW blast wall to estimate the fragility curves (FCs) of the system under free-air blast load using direct Monte Carlo (MC) simulation method. The suggested framework of the probabilistic analysis was developed to study the performance of the proposed blast wall according to the uncertainties in the structural properties and blast load parameters. The FCs were also estimated based on the variability in the equivalent TNT weight of a suicide vest threat scenario. This study recommends WSaW blast wall to reduce casualties and losses in properties in different scenarios. Furthermore, it is important to draw the attention of researchers and designer to start investigating the performance of simple blast walls iv made of other low-tech materials since it is an urgent need in most areas threatened by terrorism. v ACKNOWLEDGMENTS All praise be to Allah for helping and supporting me to reach this far and make it all possible. I want first to express my sincere gratitude to my advisors, Professor Hussam Mahmoud and Professor Paul Heyliger for the advice, and support during my Ph.D. study at Colorado State University. Special thanks to Professor Hussam Mahmoud for funding the blast tests and to Professor Paul Heyliger to organize the blast tests. I would like to thank my doctoral committee, Professor David Mclean, Professor John van de Lindt, and Professor Jennifer Mueller for their contribution in my Ph.D. research. I also thank Mr. Karl Swenson and Mr. Christopher Giglio of the Environmental Health Services at Colorado State University for their efforts in providing, handling, placing and detonating explosive charges in all implemented blast tests. I thank Dr. Kevin Troyer, Mechanical Engineering Department, and Dr. Kirk McGilvray, Mechanical Engineering Assistant research of the Orthopaedic Bioengineering Research Laboratory (OBRL) for their help in providing, dissecting, and scanning the animal tissues. Thank you to Mr. Joel Vaad the manager of Maxwell Ranch site. I would like also to express my sincere gratitude to the Iraqi Government-Prime Minister office-The Higher Committee for Education Development in Iraq (HCED) for the financial support to finish my Ph.D. study at Colorado State University. Also, not to forget to thank wife, Intisar for taking care of the family, supporting, and encouraging me throughout my academic career. Thank you to my children, Haneen, Ali, and Maria for encouraging me to continue my study successfully. Last, but not least, I thank my mother and brothers for their support, to keep me working actively to get my goals. vi DEDICATION This work is dedicated to the spirit of my father Tehseen Hussein and my younger brother Ahmad. May God have mercy on them and place them in paradise. vii TABLE OF CONTENTS CHAPTER 1. INTRODUCTION ....................................................................................... 1 1.1 Research Hypothesis ................................................................................................ 1 1.2 Research Approach ................................................................................................... 2 1.3 Research Framework ................................................................................................ 3 1.4 Dissertation Outline ................................................................................................... 5 CHAPTER 2. SUICIDE BOMBING ATTACKS: AN OVERVIEW ..................................... 7 2.1 Terrorist Attacks Scenarios and Goals ...................................................................... 7 2.2 Suicide Attacks: The Challenge ................................................................................ 8 2.3 Bombing attacks: numbers and facts ...................................................................... 10 2.3.1 The United States of America ........................................................................... 11 2.3.2 Republic of Iraq ................................................................................................. 15 2.3.3 Asia and the Middle East Countries .................................................................. 17 2.4 Economical, Demographic, and psychological Impacts of attacks in Republic of Iraq- Muqdadiyah City ........................................................................................................... 19 2.4.1 The Impact of Suicide Attacks on Lifestyle in Muqdadiyah City,